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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="lockfree.examples"></a><a class="link" href="examples.html" title="Examples">Examples</a>
</h2></div></div></div>
<h3>
<a name="lockfree.examples.h0"></a>
      <span class="phrase"><a name="lockfree.examples.queue"></a></span><a class="link" href="examples.html#lockfree.examples.queue">Queue</a>
    </h3>
<p>
      The <code class="computeroutput"><a class="link" href="../boost/lockfree/queue.html" title="Class template queue">boost::lockfree::queue</a></code>
      class implements a multi-writer/multi-reader queue. The following example shows
      how integer values are produced and consumed by 4 threads each:
    </p>
<p>
</p>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">thread</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">lockfree</span><span class="special">/</span><span class="identifier">queue</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">iostream</span><span class="special">&gt;</span>

<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">atomic</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>

<span class="identifier">boost</span><span class="special">::</span><span class="identifier">atomic_int</span> <span class="identifier">producer_count</span><span class="special">(</span><span class="number">0</span><span class="special">);</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">atomic_int</span> <span class="identifier">consumer_count</span><span class="special">(</span><span class="number">0</span><span class="special">);</span>

<span class="identifier">boost</span><span class="special">::</span><span class="identifier">lockfree</span><span class="special">::</span><span class="identifier">queue</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;</span> <span class="identifier">queue</span><span class="special">(</span><span class="number">128</span><span class="special">);</span>

<span class="keyword">const</span> <span class="keyword">int</span> <span class="identifier">iterations</span> <span class="special">=</span> <span class="number">10000000</span><span class="special">;</span>
<span class="keyword">const</span> <span class="keyword">int</span> <span class="identifier">producer_thread_count</span> <span class="special">=</span> <span class="number">4</span><span class="special">;</span>
<span class="keyword">const</span> <span class="keyword">int</span> <span class="identifier">consumer_thread_count</span> <span class="special">=</span> <span class="number">4</span><span class="special">;</span>

<span class="keyword">void</span> <span class="identifier">producer</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span>
<span class="special">{</span>
    <span class="keyword">for</span> <span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> <span class="identifier">i</span> <span class="special">!=</span> <span class="identifier">iterations</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span><span class="special">)</span> <span class="special">{</span>
        <span class="keyword">int</span> <span class="identifier">value</span> <span class="special">=</span> <span class="special">++</span><span class="identifier">producer_count</span><span class="special">;</span>
        <span class="keyword">while</span> <span class="special">(!</span><span class="identifier">queue</span><span class="special">.</span><span class="identifier">push</span><span class="special">(</span><span class="identifier">value</span><span class="special">))</span>
            <span class="special">;</span>
    <span class="special">}</span>
<span class="special">}</span>

<span class="identifier">boost</span><span class="special">::</span><span class="identifier">atomic</span><span class="special">&lt;</span><span class="keyword">bool</span><span class="special">&gt;</span> <span class="identifier">done</span> <span class="special">(</span><span class="keyword">false</span><span class="special">);</span>
<span class="keyword">void</span> <span class="identifier">consumer</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span>
<span class="special">{</span>
    <span class="keyword">int</span> <span class="identifier">value</span><span class="special">;</span>
    <span class="keyword">while</span> <span class="special">(!</span><span class="identifier">done</span><span class="special">)</span> <span class="special">{</span>
        <span class="keyword">while</span> <span class="special">(</span><span class="identifier">queue</span><span class="special">.</span><span class="identifier">pop</span><span class="special">(</span><span class="identifier">value</span><span class="special">))</span>
            <span class="special">++</span><span class="identifier">consumer_count</span><span class="special">;</span>
    <span class="special">}</span>

    <span class="keyword">while</span> <span class="special">(</span><span class="identifier">queue</span><span class="special">.</span><span class="identifier">pop</span><span class="special">(</span><span class="identifier">value</span><span class="special">))</span>
        <span class="special">++</span><span class="identifier">consumer_count</span><span class="special">;</span>
<span class="special">}</span>

<span class="keyword">int</span> <span class="identifier">main</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">argc</span><span class="special">,</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">argv</span><span class="special">[])</span>
<span class="special">{</span>
    <span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">std</span><span class="special">;</span>
    <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"boost::lockfree::queue is "</span><span class="special">;</span>
    <span class="keyword">if</span> <span class="special">(!</span><span class="identifier">queue</span><span class="special">.</span><span class="identifier">is_lock_free</span><span class="special">())</span>
        <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"not "</span><span class="special">;</span>
    <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"lockfree"</span> <span class="special">&lt;&lt;</span> <span class="identifier">endl</span><span class="special">;</span>

    <span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_group</span> <span class="identifier">producer_threads</span><span class="special">,</span> <span class="identifier">consumer_threads</span><span class="special">;</span>

    <span class="keyword">for</span> <span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> <span class="identifier">i</span> <span class="special">!=</span> <span class="identifier">producer_thread_count</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span><span class="special">)</span>
        <span class="identifier">producer_threads</span><span class="special">.</span><span class="identifier">create_thread</span><span class="special">(</span><span class="identifier">producer</span><span class="special">);</span>

    <span class="keyword">for</span> <span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> <span class="identifier">i</span> <span class="special">!=</span> <span class="identifier">consumer_thread_count</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span><span class="special">)</span>
        <span class="identifier">consumer_threads</span><span class="special">.</span><span class="identifier">create_thread</span><span class="special">(</span><span class="identifier">consumer</span><span class="special">);</span>

    <span class="identifier">producer_threads</span><span class="special">.</span><span class="identifier">join_all</span><span class="special">();</span>
    <span class="identifier">done</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span>

    <span class="identifier">consumer_threads</span><span class="special">.</span><span class="identifier">join_all</span><span class="special">();</span>

    <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"produced "</span> <span class="special">&lt;&lt;</span> <span class="identifier">producer_count</span> <span class="special">&lt;&lt;</span> <span class="string">" objects."</span> <span class="special">&lt;&lt;</span> <span class="identifier">endl</span><span class="special">;</span>
    <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"consumed "</span> <span class="special">&lt;&lt;</span> <span class="identifier">consumer_count</span> <span class="special">&lt;&lt;</span> <span class="string">" objects."</span> <span class="special">&lt;&lt;</span> <span class="identifier">endl</span><span class="special">;</span>
<span class="special">}</span>
</pre>
<p>
    </p>
<p>
      The program output is:
    </p>
<pre class="programlisting">produced 40000000 objects.
consumed 40000000 objects.
</pre>
<h3>
<a name="lockfree.examples.h1"></a>
      <span class="phrase"><a name="lockfree.examples.stack"></a></span><a class="link" href="examples.html#lockfree.examples.stack">Stack</a>
    </h3>
<p>
      The <code class="computeroutput"><a class="link" href="../boost/lockfree/stack.html" title="Class template stack">boost::lockfree::stack</a></code>
      class implements a multi-writer/multi-reader stack. The following example shows
      how integer values are produced and consumed by 4 threads each:
    </p>
<p>
</p>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">thread</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">lockfree</span><span class="special">/</span><span class="identifier">stack</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">iostream</span><span class="special">&gt;</span>

<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">atomic</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>

<span class="identifier">boost</span><span class="special">::</span><span class="identifier">atomic_int</span> <span class="identifier">producer_count</span><span class="special">(</span><span class="number">0</span><span class="special">);</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">atomic_int</span> <span class="identifier">consumer_count</span><span class="special">(</span><span class="number">0</span><span class="special">);</span>

<span class="identifier">boost</span><span class="special">::</span><span class="identifier">lockfree</span><span class="special">::</span><span class="identifier">stack</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;</span> <span class="identifier">stack</span><span class="special">(</span><span class="number">128</span><span class="special">);</span>

<span class="keyword">const</span> <span class="keyword">int</span> <span class="identifier">iterations</span> <span class="special">=</span> <span class="number">1000000</span><span class="special">;</span>
<span class="keyword">const</span> <span class="keyword">int</span> <span class="identifier">producer_thread_count</span> <span class="special">=</span> <span class="number">4</span><span class="special">;</span>
<span class="keyword">const</span> <span class="keyword">int</span> <span class="identifier">consumer_thread_count</span> <span class="special">=</span> <span class="number">4</span><span class="special">;</span>

<span class="keyword">void</span> <span class="identifier">producer</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span>
<span class="special">{</span>
    <span class="keyword">for</span> <span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> <span class="identifier">i</span> <span class="special">!=</span> <span class="identifier">iterations</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span><span class="special">)</span> <span class="special">{</span>
        <span class="keyword">int</span> <span class="identifier">value</span> <span class="special">=</span> <span class="special">++</span><span class="identifier">producer_count</span><span class="special">;</span>
        <span class="keyword">while</span> <span class="special">(!</span><span class="identifier">stack</span><span class="special">.</span><span class="identifier">push</span><span class="special">(</span><span class="identifier">value</span><span class="special">))</span>
            <span class="special">;</span>
    <span class="special">}</span>
<span class="special">}</span>

<span class="identifier">boost</span><span class="special">::</span><span class="identifier">atomic</span><span class="special">&lt;</span><span class="keyword">bool</span><span class="special">&gt;</span> <span class="identifier">done</span> <span class="special">(</span><span class="keyword">false</span><span class="special">);</span>

<span class="keyword">void</span> <span class="identifier">consumer</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span>
<span class="special">{</span>
    <span class="keyword">int</span> <span class="identifier">value</span><span class="special">;</span>
    <span class="keyword">while</span> <span class="special">(!</span><span class="identifier">done</span><span class="special">)</span> <span class="special">{</span>
        <span class="keyword">while</span> <span class="special">(</span><span class="identifier">stack</span><span class="special">.</span><span class="identifier">pop</span><span class="special">(</span><span class="identifier">value</span><span class="special">))</span>
            <span class="special">++</span><span class="identifier">consumer_count</span><span class="special">;</span>
    <span class="special">}</span>

    <span class="keyword">while</span> <span class="special">(</span><span class="identifier">stack</span><span class="special">.</span><span class="identifier">pop</span><span class="special">(</span><span class="identifier">value</span><span class="special">))</span>
        <span class="special">++</span><span class="identifier">consumer_count</span><span class="special">;</span>
<span class="special">}</span>

<span class="keyword">int</span> <span class="identifier">main</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">argc</span><span class="special">,</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">argv</span><span class="special">[])</span>
<span class="special">{</span>
    <span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">std</span><span class="special">;</span>
    <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"boost::lockfree::stack is "</span><span class="special">;</span>
    <span class="keyword">if</span> <span class="special">(!</span><span class="identifier">stack</span><span class="special">.</span><span class="identifier">is_lock_free</span><span class="special">())</span>
        <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"not "</span><span class="special">;</span>
    <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"lockfree"</span> <span class="special">&lt;&lt;</span> <span class="identifier">endl</span><span class="special">;</span>

    <span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread_group</span> <span class="identifier">producer_threads</span><span class="special">,</span> <span class="identifier">consumer_threads</span><span class="special">;</span>

    <span class="keyword">for</span> <span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> <span class="identifier">i</span> <span class="special">!=</span> <span class="identifier">producer_thread_count</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span><span class="special">)</span>
        <span class="identifier">producer_threads</span><span class="special">.</span><span class="identifier">create_thread</span><span class="special">(</span><span class="identifier">producer</span><span class="special">);</span>

    <span class="keyword">for</span> <span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> <span class="identifier">i</span> <span class="special">!=</span> <span class="identifier">consumer_thread_count</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span><span class="special">)</span>
        <span class="identifier">consumer_threads</span><span class="special">.</span><span class="identifier">create_thread</span><span class="special">(</span><span class="identifier">consumer</span><span class="special">);</span>

    <span class="identifier">producer_threads</span><span class="special">.</span><span class="identifier">join_all</span><span class="special">();</span>
    <span class="identifier">done</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span>

    <span class="identifier">consumer_threads</span><span class="special">.</span><span class="identifier">join_all</span><span class="special">();</span>

    <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"produced "</span> <span class="special">&lt;&lt;</span> <span class="identifier">producer_count</span> <span class="special">&lt;&lt;</span> <span class="string">" objects."</span> <span class="special">&lt;&lt;</span> <span class="identifier">endl</span><span class="special">;</span>
    <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"consumed "</span> <span class="special">&lt;&lt;</span> <span class="identifier">consumer_count</span> <span class="special">&lt;&lt;</span> <span class="string">" objects."</span> <span class="special">&lt;&lt;</span> <span class="identifier">endl</span><span class="special">;</span>
<span class="special">}</span>
</pre>
<p>
    </p>
<p>
      The program output is:
    </p>
<pre class="programlisting">produced 4000000 objects.
consumed 4000000 objects.
</pre>
<h3>
<a name="lockfree.examples.h2"></a>
      <span class="phrase"><a name="lockfree.examples.waitfree_single_producer_single_consumer_queue"></a></span><a class="link" href="examples.html#lockfree.examples.waitfree_single_producer_single_consumer_queue">Waitfree
      Single-Producer/Single-Consumer Queue</a>
    </h3>
<p>
      The <code class="computeroutput"><a class="link" href="../boost/lockfree/spsc_queue.html" title="Class template spsc_queue">boost::lockfree::spsc_queue</a></code>
      class implements a wait-free single-producer/single-consumer queue. The following
      example shows how integer values are produced and consumed by 2 separate threads:
    </p>
<p>
</p>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">thread</span><span class="special">/</span><span class="identifier">thread</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">lockfree</span><span class="special">/</span><span class="identifier">spsc_queue</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">iostream</span><span class="special">&gt;</span>

<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">atomic</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>

<span class="keyword">int</span> <span class="identifier">producer_count</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span>
<span class="identifier">boost</span><span class="special">::</span><span class="identifier">atomic_int</span> <span class="identifier">consumer_count</span> <span class="special">(</span><span class="number">0</span><span class="special">);</span>

<span class="identifier">boost</span><span class="special">::</span><span class="identifier">lockfree</span><span class="special">::</span><span class="identifier">spsc_queue</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">lockfree</span><span class="special">::</span><span class="identifier">capacity</span><span class="special">&lt;</span><span class="number">1024</span><span class="special">&gt;</span> <span class="special">&gt;</span> <span class="identifier">spsc_queue</span><span class="special">;</span>

<span class="keyword">const</span> <span class="keyword">int</span> <span class="identifier">iterations</span> <span class="special">=</span> <span class="number">10000000</span><span class="special">;</span>

<span class="keyword">void</span> <span class="identifier">producer</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span>
<span class="special">{</span>
    <span class="keyword">for</span> <span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> <span class="identifier">i</span> <span class="special">!=</span> <span class="identifier">iterations</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span><span class="special">)</span> <span class="special">{</span>
        <span class="keyword">int</span> <span class="identifier">value</span> <span class="special">=</span> <span class="special">++</span><span class="identifier">producer_count</span><span class="special">;</span>
        <span class="keyword">while</span> <span class="special">(!</span><span class="identifier">spsc_queue</span><span class="special">.</span><span class="identifier">push</span><span class="special">(</span><span class="identifier">value</span><span class="special">))</span>
            <span class="special">;</span>
    <span class="special">}</span>
<span class="special">}</span>

<span class="identifier">boost</span><span class="special">::</span><span class="identifier">atomic</span><span class="special">&lt;</span><span class="keyword">bool</span><span class="special">&gt;</span> <span class="identifier">done</span> <span class="special">(</span><span class="keyword">false</span><span class="special">);</span>

<span class="keyword">void</span> <span class="identifier">consumer</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span>
<span class="special">{</span>
    <span class="keyword">int</span> <span class="identifier">value</span><span class="special">;</span>
    <span class="keyword">while</span> <span class="special">(!</span><span class="identifier">done</span><span class="special">)</span> <span class="special">{</span>
        <span class="keyword">while</span> <span class="special">(</span><span class="identifier">spsc_queue</span><span class="special">.</span><span class="identifier">pop</span><span class="special">(</span><span class="identifier">value</span><span class="special">))</span>
            <span class="special">++</span><span class="identifier">consumer_count</span><span class="special">;</span>
    <span class="special">}</span>

    <span class="keyword">while</span> <span class="special">(</span><span class="identifier">spsc_queue</span><span class="special">.</span><span class="identifier">pop</span><span class="special">(</span><span class="identifier">value</span><span class="special">))</span>
        <span class="special">++</span><span class="identifier">consumer_count</span><span class="special">;</span>
<span class="special">}</span>

<span class="keyword">int</span> <span class="identifier">main</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">argc</span><span class="special">,</span> <span class="keyword">char</span><span class="special">*</span> <span class="identifier">argv</span><span class="special">[])</span>
<span class="special">{</span>
    <span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">std</span><span class="special">;</span>
    <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"boost::lockfree::queue is "</span><span class="special">;</span>
    <span class="keyword">if</span> <span class="special">(!</span><span class="identifier">spsc_queue</span><span class="special">.</span><span class="identifier">is_lock_free</span><span class="special">())</span>
        <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"not "</span><span class="special">;</span>
    <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"lockfree"</span> <span class="special">&lt;&lt;</span> <span class="identifier">endl</span><span class="special">;</span>

    <span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread</span> <span class="identifier">producer_thread</span><span class="special">(</span><span class="identifier">producer</span><span class="special">);</span>
    <span class="identifier">boost</span><span class="special">::</span><span class="identifier">thread</span> <span class="identifier">consumer_thread</span><span class="special">(</span><span class="identifier">consumer</span><span class="special">);</span>

    <span class="identifier">producer_thread</span><span class="special">.</span><span class="identifier">join</span><span class="special">();</span>
    <span class="identifier">done</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span>
    <span class="identifier">consumer_thread</span><span class="special">.</span><span class="identifier">join</span><span class="special">();</span>

    <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"produced "</span> <span class="special">&lt;&lt;</span> <span class="identifier">producer_count</span> <span class="special">&lt;&lt;</span> <span class="string">" objects."</span> <span class="special">&lt;&lt;</span> <span class="identifier">endl</span><span class="special">;</span>
    <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"consumed "</span> <span class="special">&lt;&lt;</span> <span class="identifier">consumer_count</span> <span class="special">&lt;&lt;</span> <span class="string">" objects."</span> <span class="special">&lt;&lt;</span> <span class="identifier">endl</span><span class="special">;</span>
<span class="special">}</span>
</pre>
<p>
    </p>
<p>
      The program output is:
    </p>
<pre class="programlisting">produced 10000000 objects.
consumed 10000000 objects.
</pre>
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      Blechmann<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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